The present invention relates to a system for detecting a leak of fluid from a long pipeline for transporting fluid such as town gas, natural gas, oil or the like.
In recent years, pipelines have been used extensively for long distance transport of fluid. The longer the pipeline, the more difficult it is to detect a leak of fluid from the pipe and generally a long period of time elapses before a fluid leak is found. Particularly in the case where the fluid transported by the pipeline is inflammable, explosive or toxic, the delay in the detection of the leak is liable to cause a serious accident. Accordingly, there is a need to provide a system for detecting a leak which is practically applicable to industries and which enables the operator from his place such as a monitoring station to promptly reliably detect any leak no matter where it may occur in a long pipeline. It is further desired to provide a system by which the operator from his place such as a monitoring station can locate the leak, namely a system capable of pinpoint detection.
Various means for detecting a leak of fluid from the pipe have heretofore been used, but none of the conventional means fulfilled the above-mentioned needs. More specifically, already known is a detecting apparatus such as an ultrasonic gas leak detector and a water leak detector which detects the leak of fluid from the pipe by utilizing an elastic wave caused by the fluid leakage. However, such apparatus fails to achieve a reliable leak detection unless the elastic wave utilized has a considerable intensity and is distinct from other elastic waves. In fact, the conventional apparatus of this type can not detect the leak if it is not within the reach of several meters, so that the apparatus has to be carried about by the operator for the detection of the leak. Thus a leak detection for a long pipeline has heretofore required much labor and time, and even at the expense of much labor, it has been practically impossible to detect the leak immediately after the occurrence of the leak.
Another apparatus has also been proposed which, like an inflammable gas detector, detects a leak of fluid by utilizing chemical and physical properties of the fluid. With the apparatus of this type, however, there is a need to intercept the leaked fluid by the apparatus per se, with the result that such apparatus is generally capable of local detection only, is less reliable in detecting leaks, takes a long period of time to detect the leak and is limited with respect to objects for which it is serviceable for detection.